Metal Recovery from Sludge through the Combination of Hydrothermal Sulfidation and Flotation

AbstractThe heavy metal in the waste can react with sulfur and be converted to metal sulfide through the hydrothermal sulfidation. For metal recovery, the synthetic metal sulfide can be enriched through subsequent flotation process. It is a novel way for the recovery of heavy metal from the sludge. In this study, the effects of liquid/solid ratio, mineralizer concentration, precursor concentration and dosage of sulfur on the sulfidation extent and floatation index were investigated. Result shows that with a precursor concentration of 15%, a Zn/S molar ratio of 1:1.2, a liquid/solid ratio of 3:1, the sulfidation extent of zinc in the sludge was greater than 92%, while the flotation recovery of zinc reached up to 45.34%. The toxicity characteristic leaching procedure (TCLP) revealed that stabilization and detoxification of heavy metals occurred during sulfidation

Preparation of Antibacterial Color-Coated Steel Sheets

A simple method to fabricate antibacterial color-coated steel sheet was presented. The Ag-loaded TiO2 was well dispersed in steel coil coating coupled with some special additives, such as plasticizer, wetting dispersant, and flow agent, and finally became the part of coil coating without any negative influence on the properties of final products. The best process parameters were obtained by substantive trial experiments. Ag-loaded TiO2 with the addition of 2% (w/w) in steel coil coating not only improved antibacterial efficiency of the antibacterial color-coated sheet by reaching 99.99%, but also greatly increased the degradation percentage of methyl orange to 88% without decreasing physical properties. The antibacterial color-coated sheets are expected to be used as antimicrobial products in the construction industry considering its low cost and high effectiveness in inhibiting the growth of bacteria

Heteroatoms Induce Localization of the Electric Field and Promote a Wide Potential-Window Selectivity Towards CO in the CO2 Electroreduction

Carbon dioxide electroreduction (CO2RR) is a sustainable way of producing carbon-neutral fuels. Product selectivity in CO2RR is regulated by the adsorption energy of reaction-intermediates. Here, we employ differential phase contrast-scanning transmission electron microscopy (DPC-STEM) to demonstrate that Sn heteroatoms on a Ag catalyst generate very strong and atomically localized electric fields. In situ attenuated total reflection infrared spectroscopy (ATR-IR) results verified that the localized electric field enhances the adsorption of *COOH, thus favoring the production of CO during CO2RR. The Ag/Sn catalyst exhibits an approximately 100 % CO selectivity at a very wide range of potentials (from -0.5 to -1.1 V, versus reversible hydrogen electrode), and with a remarkably high energy efficiency (EE) of 76.1 %

Two-Dimensional Titanium Carbides (Ti3C2Tx) Functionalized by Poly(m-phenylenediamine) for Efficient Adsorption and Reduction of Hexavalent Chromium

Titanium carbides (MXenes) are promising multifunctional materials. However, the negative surface charge and layer-by-layer restacking of MXenes severely restrict their application in the field of anionic pollutants, including in hexavalent chromium (Cr(VI)). Herein, Ti3C2Tx MXenes was functionalized through in situ polymerization and intercalation of poly(m-phenylenediamine) (PmPD), then Ti3C2Tx/PmPD composites were obtained. Delightedly, Ti3C2Tx/PmPD composites exhibited positive surface charge, expanded interlayer spacing, and enhanced hydrophobicity. Furthermore, the specific surface area of Ti3C2Tx/PmPD composite was five and 23 times that of Ti3C2Tx and PmPD, respectively. These advantages endowed Ti3C2Tx/PmPD composite with an excellent adsorption capacity of Cr(VI) (540.47 mg g−1), which was superior to PmPD (384.73 mg g−1), Ti3C2Tx MXene (137.45 mg g−1), and the reported MXene-based adsorbents. The Cr(VI) removal mechanism mainly involved electrostatic adsorption, reduction, and chelation interaction. This study developed a simple functionalization strategy, which would greatly explore the potential of MXenes in the field of anionic pollutants

A series piezoelectric quartz crystal response model for ferrous ion oxidation in the presence of <i>T. ferrooxdians</i>

939-942A novel and simple method, series piezoelectric quartz crystal (SPQC) has been used to monitor ferrous ion oxidation in the presence of T. ferrooxidans. By combination of a general SPQC response model with the kinetics of the bacterial growth, a SPQC response model for ferrous ion oxidation in the presence of T.ferrooxidans has been built. The response model can describe the bacterial growth process well. Some important kinetic parameters, such as μm (the maximum specific growth rate of bacterium), K (saturation constant, i.e., the ferrous iron concentration at which the half-maximal growth rate occurs), X0 / Y (ratio of initial bacterial concentration to cell yield coefficient), have been obtained by fitting the model to the experimental curves

Hexakis(&amp;#956;3-2-hydroxynaphthalene-1-carboxaldehyde thiosemicarbazonato-&amp;#954;3N2:S:S)hexasilver(I) N,N-dimethylformamide tetrasolvate

In the title compound, [Ag6(C12H10N3OS)6]&amp;#183;4C3H7NO, the hexanuclear complex molecule lies about an inversion center. The six Ag atoms form a distorted octahedron, with Ag...Ag distances in the range 2.933&amp;#8197;(1)&amp;#8211;3.401&amp;#8197;(1)&amp;#8197;&amp;#197;. Each Ag atom is surrounded by one N atom and two thiolate S atoms from two deprotonated 2-hydroxy-1-naphthaldehyde thiosemicarbazone ligands. Each ligand coordinates three Ag atoms via a bridging thiolate S atom and a monodentate N atom, thus two Ag3S3 hexagonal rings are linked together. Two dimethylformamide solvent molecules are located in four sets of sites with half-occupancy and form O...H&amp;#8212;N hydrogen bonds to the complex molecule. Intramolecular O&amp;#8212;H...N hydrogen bonds are also present. The discrete hexanuclear clusters are further linked through &amp;#960;&amp;#8211;&amp;#960; interactions into layers parallel to (001), the shortest distance between the centroids of aromatic rings being 3.698&amp;#8197;(2)&amp;#8197;&amp;#197;

Scanning Calorimetric Detections Of Multiple Dna Biomarkers Contained In Complex Fluids

Most of the existing techniques cannot be used to detect molecular biomarkers contained in complex fluids due to issues such as enzyme inhibition or signal interference. We have developed a nanoparticle-based scanning calorimetric method for the highly sensitive detections of multiple DNA biomarkers contained in cell lysate and milk by using solid-liquid phase change nanoparticles as thermal barcodes. The detection is based on the principle that the temperature of solid will not rise above the melting temperature unless all solid is molten, thus nanoparticles have sharp melting peaks during the thermal scan process. A one-to-one correspondence can thus be created between one type of nanoparticles and one type of biomarker, i.e., multiple biomarkers can be detected at the same time using a combination of nanoparticles. The melting temperature and the heat flow reflect the type and the concentration of the biomarker, respectively. The target oligonucleotides at low concentration in cell lysate (80 pM) have been detected through thermal signal transduction. The melting temperature of nanoparticles can be designed to avoid interference from coexisting species contained in the fluids, bringing simultaneously high sensitivity and multiplicity, as well as sample preparation benefits to biomarker detections. © 2010 American Chemical Society